3,166 research outputs found

    A model of an optical biosensor detecting environment

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    Heller et. Al. (Science 311, 508 (2006)) demonstrated the first DNA-CN optical sensor by wrapping a piece of double-stranded DNA around the surface of single-walled carbon nanotubes (CN). This new type of optical device can be placed inside living cells and detect trace amounts of harmful contaminants by means of near infrared light. Using a simple exciton theory in nanostructures and the phenomena of B-Z structural phase transition of DNA, we investigate the working principle of this new class of optical biosensor from DNA by using the nanostructure surface as a sensor to detect the property change of DNA as it responds to the presence of target ions. We also propose some new design models by replacing carbon nanotubes with graphene ribbon semiconductors.Comment: 4 pages, 4 figures, Accepte

    Liberty and the Rule of Law After September 11

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    The topic of this paper is liberty and the rule of law in a post- 9/11 society. Their relationship is frequently presented as a trade-off, as if somehow liberty must yield in order to preserve national security at a time when we feel insecure as a nation and unsafe as people. At the core of this conversation are the essential questions: What does one mean by liberty? What does one mean by security
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